In use, a computer may crash or begin operating in a non-desired manner. For example, a hard drive may malfunction, a component may fail, or software that used to work may stop functioning correctly. A malfunction may be caused by a variety of sources including environmental causes (e.g., lightning), computer viruses, or user error (e.g., deleting a software component, reconfiguring a software component, and so forth).
One response to a malfunction is, where possible, to restore the computer to a previous state. This may involve locating recovery tapes, executing recovery software, and restoring a backup of a previous state of the computer. Often, in such a recovery process, data and configuration that currently exists on the computer is erased or overwritten when restoring the previous state. Additional data and configuration that was created after the previous backup but before the malfunction is lost. In addition, the user may not know when the malfunction first commenced. In both cases, restoring a previous backup may not return the computer to an acceptable state.